1. Field of the Invention 
This invention relates to a collapsible feeder and more particularly to a collapsible feeder for birds, squirrels and the like which is convenient to fill, convenient to install, convenient for wild game to perch upon, and which is resistant to damage from squirrels and other feeding wildlife. Even more particularly, the collapsible feeder of this invention includes means for yieldably maintaining the feeder in its extended position while the feeder is being filled and/or hung. 
2. Description of the Related Art 
Selectively collapsible containers are commonly used to hold seeds, suet and the like as food for wild animals such as birds, squirrels, etc. Many of the collapsible wild game feeders of the prior art are constructed from plastic polymer, natural fiber mesh or netting. Mesh or netting feeders have the advantage of not requiring a rod, dowel or other support for small birds, since the birds can perch on the mesh or net and feed at any exposed location on the feeder. Examples of mesh or net feeders of the prior art including the Thistle Pouch brand feeder manufactured by Havegard Farm, Inc. of Algoma, Wis., and Feather Friends E-Z Feeders brand wild bird feeder marketed by Canine's Choice of Marion, Ind. Other types of collapsible feeders are disclosed in U.S. Pat. Nos. 5,203,281; 4,706,851 and 4,026,244. Another type of collapsible wild game feeder is described in applicant's U.S. Pat. No. 5,479,881. The feeder of the '881 patent consists of a solid, weather-resistant bag fitted with openings at its base to allow attachment of rods for perching and access to the seed or other food contained in the bag.  
Although many collapsible wild game feeders of the known art are convenient to install and highly attractive to wild game when they are first placed in use, none of the collapsible feeders of the known art are suitable for the feeding of squirrels or other large, aggressive feeding wildlife such as jays and monk parakeets. Squirrels and other large, aggressive feeding wildlife quickly tear the mesh of collapsible feeders of the known art and create holes through which the food spills from the feeder onto the ground below. Similarly, squirrels and large birds can easily enlarge the feeding openings or simply create new openings in the walls of the feeder of the '881 patent. After squirrels or large birds have damaged the net, webbing or walls of feeders of the known art, the food spills out and is no longer available to attract wildlife to the feeder. Further, the spilled feed creates additional problems by attracting mice and other pests that feed on the ground.  
Wire mesh feeders constructed of rigid steel wire are also well known to those skilled in the art of wild game feeding. The rigid steel wire mesh feeders are frequently used to hold blocks of suet or mixtures of seed, animal fat, peanut butter and the like. Although the rigid wire mesh feeders of the known art are resistant to chewing by squirrels and pecking by aggressive feeding birds, the rigid wire mesh feeders are not selectively collapsible for storage, shipment, etc. When the rigid wire mesh feeders are bent, dented, flattened or crushed, they cannot be expanded and reused without suffering metal fatigue and damage to their attachments, connections and welds. One further disadvantage of many collapsible feeders is that they are suited for only one size of feed. 
In an effort to overcome the disadvantages of the prior art collapsible feeders, applicant previously designed collapsible feeders which are disclosed in U.S. Pat. Nos. 6,047,661 and 6,073,582. In the '661 and '582 patents, the mesh openings were designed to accommodate a specific seed size. Applicant provided an improved collapsible feeder which is disclosed in U.S. Pat. No. 6,427,629 which issued on Aug. 6, 2002. Although applicant's feeder of U.S. Pat. No. 6,427,629 truly represented an improvement over the prior art, the feeder sometimes would not remain in its extended position while the feeder was being filled or hung which sometimes resulted in feed flowing from the feeder from between adjacent rings. The feeders of applicant's earlier patents truly represented a significant advance in the art and it is believed that the collapsible feeder described herein represents an improvement over applicant's earlier designs.  